Effect of birth year on birth weight and obesity in adulthood: comparison between subjects born prior to and during the great depression in Iceland.

1Unit for Nutrition Research, Landspitali University Hospital and Faculty of Food Science and Nutrition, School of Health Sciences, University of Iceland, Reykjavik, Iceland. cmi1@hi.is

Abstract

BACKGROUND:

Many epidemiological studies have linked small size at birth to adverse adult health outcomes but the relative influence of environmental exposures is less well established.

METHODS:

The authors investigated the impact of prenatal environmental exposure by comparing 2750 participants born before (1925-1929) and during (1930-1934) the Great Depression in Reykjavik, Iceland. Calendar year served as proxy for environmental effects. Anthropometric measurements at birth and school-age (8-13 years) were collected from national registries. Participants were medically examined as adults (33-65 years).

CONCLUSION:

Reduction in birth weight due to rapid shifts in the economic environment appears to have a modest but significant association with later obesity for women while male offspring appear to be less affected by these conditions.

Yearly birth weight for men (diamond) and women (square) born between 1925 and 1934.

Footer: Data are shown as means and the bars denote the standard error of the means. Birth weight is further stratified by sex and grouped by birth during pre-Depression (1925–1929) and during the Depression (1930–1934).

Yearly ponderal indexa for men (diamond) and women (square) born between 1925 and 1934.

Footer: Data are shown as means and the bars denote the standard error of the means. Ponderal index is further stratified by sex and grouped by birth during pre-Depression (1925–1929) and during the Depression (1930–1934). a Ponderal index = (birth weight in g/birth length in cm3*100).

Footer: Subjects born pre-Depression (1925–1929) were growing up during the Depression; while subjects born during the Depression (1930–1934) were growing up after the Depression and had faster BMI gain, growing closer to the 50th percentile for the WHO BMI-for-age standards compared to their counterparts born earlier. *Significant difference between BMI values of participants born pre-Depression vs. during the Depression, adjusted for maternal age and parity (P<0.05).